[CH3:1][N:2]([CH3:9])[C:3](=[O:8])[C:4]([O:6][CH3:7])=[O:5].[CH:10]1(O)[CH2:15][CH2:14]C[CH2:12][CH2:11]1.S(=O)(=O)(O)O>CO>[CH3:1][N:2]([CH3:9])[C:3](=[O:8])[C:4]([O:6][CH:7]1[CH2:14][CH2:15][CH2:10][CH2:11][CH2:12]1)=[O:5]In a 1,000 mL reactor, are mixed at 20-25° C., methyl 2-(dimethylamino)-2-oxoacetate) (compound 1) (393 g, 3 mol), cyclohexanol (360 g, 3.6 mol) and 98% sulfuric acid (66 g, 0.67 mol). The temperature of the mixture is brought to and maintained at 80° C. for 36 hours. Progression of the reaction is followed by gas chromatography analysis. At the end of the reaction, the methanol formed is removed from the reaction medium by distillation under reduced vacuum (P min=150 mbars) and an aqueous solution of sodium hydrogen carbonate is then added to the reaction medium so that the final pH is 7. The organic phase is separated from the aqueous phase. The latter is counter-extracted with 500 mL of dichloromethane. The organic phases are collected and the reaction medium is then concentrated for removing the dichloromethane. To the residue are added 5 g of potassium carbonate and the thereby obtained medium is then distilled under partial vacuum (Tbp 115-120° C., P<1 mbar). The expected product is obtained with a purity of more than 98.2% (466 g).
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